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Characterizing soil salinity at the regional scale remains challenging despite decades of effort in soil mapping. Using satellite remote sensing, an effort has been made to identify the coastal saline soils in India. The study made use of the OLI sensor of the Landsat-8 satellite. The images were downloaded from the USGS EarthExplorer website. For multi-temporal studies, absolute radiometric calibration was done to minimize the impacts of changing atmospheric conditions, solar inclination and sensor view angle. Images were categorized using unsupervised classification, while a ground survey and Google Earth data were used for ground truthing. Three indices, namely normalized difference vegetation index (NDVI), salinity index (SI), and canopy response salinity index (CRSI), were used to identify soil salinity regions. For testing the vegetation index with soil salinity, 192 georeferenced soil samples from the Indian Sundarbans were collected. A relationship was developed between NDVI, SI and square of CRSI (CRSISQR) with ECe (electrical conductivity of saturation paste extract) and EC1:2 (1: 2; soil: water). For the coastal region, soils with CRSISQR < 0.16 were considered to be influenced by salinity since the relationship between ECe and CRSISQR had a maximum R² (0.50). It has been estimated that India has 12.94 lakh ha of saline soil within arable lands in all the coastal districts, and Gujarat (5.28 lakh ha), West Bengal (5.08 lakh ha), and Andhra Pradesh (1.06 lakh ha) were identified as the top three-salinity affected coastal states in the country. [ABSTRACT FROM AUTHOR]

Rhynchosia minima is prostrate climbing herb. In India it flowers during September-March with peak flowering during January. The flowers are hermaphroditic, nectariferous, self-compatible and have explosive pollination mechanism adapted for pollination by bees. They do not fruit through autonomous selfing but fruit through manipulated selfing, geitonogamy and xenogamy mediated by pollen vectoring bees. The flowers not visited by bees fall off while those visited and pollinated by them set fruit. Seed dispersal occurs by explosive pod dehiscence. Perennial root stock resurrects back to life during rainy season. Seeds also germinate at the same time but their continued growth is subject to the availability of soil moisture content. Therefore, R. minima expands its population size and succeeds as a weed in water-saturated habitats only. The plant is used as medicine, animal forage and human food and hence it has the potential for exploitation commercially. [ABSTRACT FROM AUTHOR]

The experiment was conducted on a clay loam soil in sugarcane plant-ratoon system at Regional Agricultural Research Station, Anakapalle with a variety 93 A 145 during 2007-08 and 2008-09 to study the comparative performance of effect of different organic manures on soil health and yield of sugarcane. Results revealed that the addition of different organic manures in addition to recommended dose of fertilizers (RDF) resulted in the higher organic carbon content and available nutrient status of the soil compared to chemical fertilizers alone. The plots which received FYM @ 25 t/ha +RDF recorded highest organic carbon (0.55 %) and available N (226 kg/ha). However maximum available P2O5 and K2O (38.89 & 254 kg/ha) was observed in plots which received press mud cake @ 12t/ha +RDF as press mud cake is a rich source of phosphorus (2.76 %). Decrease in pH in manured plots was attributed to increase in partial pressure of CO2 and organic acids due to organic matter decomposition. Slight increase in soil organic carbon content and available nutrient status was observed in ratoon crop than plant crop is due to residual and cumulative effects of added organic manures in ratoon crop. The highest N uptake (301 kg/ha) was recorded with the treatment which received RDF + vermicompost. However maximum phosphorus uptake of 54.11 and 58.96 kg/ha (plant and ratoon crop respectively) was recorded in the treatment which received press mud cake + RDF is due to maximum P availability when compared to other sources. Better juice quality was observed in manure treated plots than RDF alone. Maximum juice sucrose (19.75 %) and % CCS (13.72) was observed in FYM + RDF of plant crop. Farm Yard Manure+ RDF registered higher cane yield (94.18 t/ha) and sugar yield (12.92 t/ha) than application of entire 'N' through RDF alone (cane yield: 87.42 t/ha and sugar yield : 11.06 t/ha) but was found at par with vermicompost + RDF (cane yield 93.88 t/ha; sugar yield : 12.59 t/ha). The study showed that integrated use of organic manures and inorganic fertilizers produced higher and sustainable cane yields and maintained the soil fertility (Organic manures, soil fertility, productivity and sugarcane). [ABSTRACT FROM AUTHOR]